Known techniques pertaining to production of a pulp molded article using two kinds of cores include Japanese Patent 78600. The patented technique comprises arranging a solid core and a bag-like core in an outer mold (papermaking mold), accumulating pulp fiber on the papermaking surface of the outer mold to form a wet molded article, supplying a prescribed fluid in the bag-like core to expand it, pressing the molded article by the expanded core toward the papermaking surface to dewater the molded article. The molded article is removed from the mold and dried to obtain a molded article of prescribed shape.
According to this pulp molded article production method, the part of the molded article that has an increased density by pressing with the bag-like pressing member exhibits high strength. However, the other part is liable to become uneven in thickness and density and, after dewatering and drying, the molded article tends to suffer from thickness or density variation and resultant non-uniformity in physical properties such as strength.
The technique disclosed in JP-A-2000-239998, which relates to production of a pulp molded article, makes it possible to produce a hollow pulp molded article of a complicated shape. There is a demand for establishing means for making a fiber molded article of a complicated shape, particularly a fiber molded article having a partial protrusion or a wide opening, at a precise shaping with minimized variation in thickness and density. In manufacturing a molded article of a complicated shape, since the pressing member used to press a molded article has poor durability due to partial inflation, it has been desirous of a durable mold for producing a fiber molded article.
Accordingly, an object of the present invention is to provide a high durable pressing mold for producing a fiber molded article having a complicated shape, particularly having a partial protrusion or a wide opening portion at a high precise shaping with minimized variation in thickness; and a method of producing a fiber molded article using such a pressing mold.